Electric switch



June 26, 1928.

- Filed Nova l9 45 shown in Figure 4;

, Patented'June 26, 1928.. v

UNITED. STATES PATENT 1,675,185 OFFICE.

.ToIIIv LOFGREN, or CHICAGO, IL IIvoIs ASSIGNOR ro'nALco MANUFACTURING comram, or CHICAGO, ILLINOIS,

A CORPORATION or ILLINOIS.

. sesame SWITCH.

"Application fled Kovember 2, I925. Serial No. 66,141.

My invention relates 'to electric switches, especially for locomotiveheadlights and for use in other places where a rugged, durable switch is required-and one which;can be relied'upon to maintain the position inwhich it is set, regardless of shocksand' jars 1n;

cidental to severe operating conditions. One of the objects of myinvention is to provide a switch having a rotatable shaft for controlling the circuit and a simple and efiective .lock for with the first is to provide a lock of imposi tive character whereby areasonable amount of torque applied to the shaft by hand will rotate it and overcome the locking effect. Still another object is to provide simple and eflicient means for'sup orting the bridging elementon the shaft thoroughly insulating it fromthe shaftand from the switch housing.

I I1 accomplish my objects'by the mechanism illustrated in the accompanying drawis shown removed ings, in which Figure 1 is a top assembly view of a switch embodying the invention. The cover ing theinternal construction. 'f I Figure 2 is a sectional view on the. line 2-2 Figure '1. 1

Figure 3-,is a 3.3 Figure .2. a I v Figure 4 is a view taken on theline4-4 Figure 3, and showing the bridging ele- "ment and associated parts.

' Figure 5 is a perspective view of, the rotatable shaft. I

Figure 6 is a distributive view of the bridging element and.- associated insulating washers, showing their forms and suggesting the manner in which they are assembled. Figure 7 is a fragmentary detail showing the switch terminals and associated parts when the switch is on open circuit, as distinguished from the closed circuit. position sectional view on the line parts throughvgated in such manner that preventing accidental rota-E 'tion of the shaft. Another object, associatedand at the same' time for the purpose of reveal- I Y and washers as best 2. The washers have slots 40 at thecenter, which enable them to make a sliding 'fit with the stem 32. The result is that the Suitably mounted within the housing, and electrically connected to the conductors 18, 19 are two spring switch terminals 22. Be tween these terminals is a ibridging element 24 of conductive material, which is elonwhen rotatedv to one it wi l engage the terminals and electrically connect them, but when rotated to a position approximately at right angles, as shownin Figure 7, it will be out of contact with said terminals and hence break the circuit.

position, as; shown in Figures 1- to 4,

According to the design illustrated the bridging element 24 is controlled by a shaft 26, which is journaled within a bearing or housing 28 having wings 30 by which it-is bolted to the housing 10 as best shown in Figures land 3. The shaft has a flattened stem 32 lying inside of the main housing 10. The bridging element 24 has a central open-' ing 34 which is large enough to freely accommodate the stemwithout touching it, as will be evident by reference to Figure '3. There is ani'nsulating washer36 on each side of the bridging element, these washers being fastened to the bridging element by pins'38, which pass through the bridging element gure illustrated in Fi washers are supported upon the stem androtated by it. 1

On the outer side of each washer 36 is' an outer washer 42, which is also slotted in such ure 3. This constructionand arrangement of parts has several advantages. One Is a 95. parts assembled as best illustrated in Fig- 1 that. it is extremely simple. The washers 36 can readily be formed by punching, after which the pins 38 are simply slipped into place. The outer washers 42 cbnfine the pins and at the same time insulate them from the associated parts. .-Another ad vantage is that the bridging element and is that the washers, being interposed. te-

pins are very thoroughly insulated from the shaft andfrom the main housing ofthe deing normally to force lar position with respect to the switch casat the sides so as to be cam-like,

tween the switch terminals 22 when the bridging element is in'open circuit position, as in Figure T, serve as spreaders for the terminals and prevent them from reaching the side of, the bridging element... To gain this effect the diameter ofthe washers is greater than the width of the bridging ele- 'ment, so that the washers project beyond the edges of the bridging element. The length of the bridging element, however, is greater than the diameter of the washers so it may make contact with the terminal when rotated to closed circuit position shown in Figure 4:.

The shaft 26 is rotated by means of a handle 48 which by preference is cast integral with it. On the inner side this handle has two lugs 50 designed to seat in recesses 52 formed in the end of the housing 28. In other words the portions 50, 52 constitute inter-fitting parts which tend to prevent rotation of theushaft when the interfitting parts are seated. These parts are inclined with the result that torque applied to the shaft tends to induce a longitudinal movement of the shaft and an unseating of the interfitting parts as well as a rotary movement of theshaft. The recesses 52 are arranged 90 degrees apart so that the interfitting parts will seat in either of two positions at right angles to each other.

The interfitt-ing parts tend to be held seated by means of a helical compression spring 54, which surrounds the shaft, and at one end abuts against the outer end of the housing 28' and at the inner end abuts against a collar 56 formed on the shaft near the inner end of the housing 28, as best shown in Figure 3. The result of this construction is that an impositive lock is formed, and the spring will normally hold the interfitting parts snugly seated and thus prevent any rotation of the shaft, although when the operator desires to rotate the shaft he may do so by exerting a reasonable amount of torque upon the handle 48.

. Having thus described my invention what I claim as new and desire to secure by Let-.

ters Patent is:

1. In an electric switch the combination of a casing having switch terminals therein spaced apart, an angularly movable and longitudinal slidable shaft mounted on said casing and having its innerends disposed between said switch terminals, a spring surrounding a portion of said shaft and tendthe shaft in one direction, (ac-operative locking means on the shaft and on the switch casing for impositively holding the shaft in a predetermined anguing, said portion of the shaft'disposed between the switch terminals being angular in cross section, a plurality of insulating washthe ends of said pins being confined in posi .tion by said washers.

2. In an electrical switch the combination of a casing having switch terminals, a switch operating shaft mounted in the casing and having its inner end of angular cross section and disposed between the switch terminals, said shaft being mounted for both longi tudinal movement andv angular movement,

means cooperating with the longitudinal,

movement of said shaft for impositively locking the shaft from angular movement, a plurality of insulating washers slidably mounted on the angular portion of said shaft to rotate with said-shaft, an elongated large bridging elementmounted on said shaft between certain of said washers and having a relatively large bore surrounding and spaced from the shaft, means for rigidly connecting said bridging element with said washers to move the bridging element angularly when the washers are moved angularly.

3. In an electric switch the combination of a casing having switch terminals, said casing having a lateral outstanding projection provided with a hollow boss, a shaft mounted in said boss, said shaft having an outer turning handle and a head spaced from the handle, said head slidably fitting within said boss, a coil spring in said boss between vsaid head and the end of the boss, cam shaped locking detent on the inner face of the turning handle of the shaft, the inner end of theshaft having an angular portion,

a plurality of washers mounted on said angular portion longitudinally relatively thereto and an elonv to rotate therewith but slidable gated bridging element mounted on said washers and having a central bore surrounding and spaced from said shaft, a means for connecting said bridging element with certain of said washers! 4. In an electric switch the combination of a casing having switch terminals, a switch shaft mounted on the casing and having an innerhead forming a shoulder and an inner" angular portion disposed between said termis nals, a plurality of washers having central openings corresponding to the cross section of the angular portion of the shaft andcertain of which have marginal spaced apart holes, said washersbeing disposed on said bridging element having a relatively large bore surrounding and spaced from said shaft, an elongated bridging element disposed between certain of said washers, said shaft and having marginal holes adapted to register with the marginal holes of certain of said washers, detachable pins passing, through the marginal holes of certain of said washers and the bridging element, and

other washers having imperforate portions in registry Wltll the marginal holes of the first mentioned washer, said second menb said terminals, a longitudinal slidable switch.

operating shaft having its inner end of angular section and disposed between said switch terminals and passing through a relatively large bore in the bridging element so as to be insulated therefrom, insulating Washers mounted on said shaft for angular movement therewith, and slidably relative to said shaft to permit the free endw ise movement of said shaft and means for interconnecting the insulating washers and thebridging element for driving the bridging element through the intermediary of the insulating washers and an impositive locking mechanism operated by the longitudinal movement of the switch shaft for holding the bridging element in desired angular position with respect to the switch terminals.

6.- In an electric switch, the combination of .switch terminals, 2; connected rotary ridging element for electrically connecting and disconnecting said terminals and an insulating washer at the side of the bridging element between the terminals, the diameter of the Washer beinggreater than the width and, less than the length of the. bridging element whereby when the bridging element'is in one position it will makejcontact with the terminals and when rotated at approximately right angles, the washer will'prevent the terminals from; reaching the side of the bridging element', a shaft .slidably passing through the bridging element and vwasher and insulated from the bridging element and an impositive locking mechanism adapted to be operated by the slidable movement of said shaft for impositively holding J the a bridging element in desired shifted position. In witness whereof, I have hereunto subscribed my name. 1 I a JOHN LOFGREN. 

